Reign periods, or nianhao, constitute a basic unit of the Chinese calendar. Traditionally, dates are given as year XX of the YY reign period. The third year of the Chenghua period is 1467, since the first year was in 1464 when the Yongzheng Emperor began his rule. The name of a nianhao is actually an auspicious title or slogan chosen to indicate and support a political direction. Originally, emperors could have several such titles during their years on the throne, changing them when a new direction was instituted.
Starting from the Ming dynasty, however, the custom of picking new titles disappeared and each emperor used a single nianhao during the entire span of his reign. When a new emperor ascended the throne, they picked a new title. As a result, the reign titles became associated with, and designate, the ruler. So when we talk about the Chenghua Emperor then, although “Chenghua” is actually not the emperor’s name (real name Zhu Jianshen) but a title chosen at the beginning of his rule, it is perfectly clear who we mean by that designation.